Born on his father's farm near St. Louis, MO, he graduated from West Point on July 1, 1843 with a brevet to 2nd Lieutenant, 6th Infantry. Of this class of 39 men, 27 were living in 1861 and 15 became general officers of full rank in the Union or Confederate armies, one of whom was Ulysses S. Grant, who Dent introduced to his sister who later became Grant's wife. He served on Frontier Duty at Ft. Towson, Indian Territory, 1843-1846 and in garrison at Baton Rouge, LA, 1846-1847. He was promoted to 2nd Lieutenant, 5th Infantry, March 30, 1846.

In the War with Mexico, he was engaged in the Siege of Vera Cruz, March 9-29, 1847; Capture of San Antonio, August 20, 1847 and the Battle of Churubusco, August 20, 1847. He was breveted to 1st Lieutenant, August 20, 1847, for gallant and meritorious conduct in the Battles of Contreras and Churubusco. He was next engaged in the Battle of Molino del Rey, September 8, 1847, where he was severely wounded. He was breveted to Captain, September 8, 1847, for gallant and meritorious conduct at the Battle of Molino del Rey and promoted to 1st Lieutenant, 5th Infantry, September 11, 1847.

Dent was in garrison at Baton Rouge, LA, 1848 and on the Pacific Railroad Survey, 1849. He served on Frontier Duty, at Ft. Gibson, Indian Territory, 1849-1850; Removing Seminole Indians, 1850-1851; at Ft. Gibson, Indian Territory, 1851; on the March to Texas, 1851; at Ft. Belknap, TX, 1851; Clear Fork of the Brazos River, TX, 1851-1853; and Ft. McIntosh, TX, 1853-1854. He was on Recruiting Service, 1854- 1855 and in garrison at Ft. Monroe, VA, 1855, being promoted to Captain, 9th Infantry, March 3, 1855.

He served on Frontier Duty at Ft. Vancouver, WA, 1856; Scouting, 1856, being engaged in a Skirmish on the Cedar River; on the Yakima Expedition, 1856; at Ft. Dalles, OR, 1856-1857; Ft. Hoskins, OR, 1857; Ft. Dalles, 1857; and Ft. Walla Walla, WA, 1857-1858. On the Spokane Expedition, WA, he was engaged in the Combat at Four Lakes, September 1, 1858; Combat on Spokane Plain, September 5, 1858; and Skirmish on Spokane River, September 8, 1858. He returned to Frontier Duty at Ft. Walla Walla, WA, 1858-1860; on the Expedition to Snake River, OR, to rescue survivors of the Massacre at Salmon Fall, 1860; at Ft. Hoskins, OR, 1861 and San Francisco, CA, 1861-1863. He was promoted to Major, 4th Infantry, March 9, 1863.

Dent served in command of Regiment in the Army of the Potomac, August 12-September 8, 1863; in New York to suppress anticipated riots, September 10, 1863 to January 17, 1864; and as Member of Military Commission for the Trial of State Prisoners, January 17-March 29, 1864. He was promoted to Lieutenant Colonel, Staff, March 29,1864, and assigned as Aide-de-Camp to the General-in-Chief, Lieutenant-General Ulysses S. Grant, March 29, 1864-April 19, 1865, being present in the Battles and Military Operations of the Richmond Campaign, 1864-1865; and as Military Commander of the City of Richmond, VA, April 19-May 27, 1865.

He was breveted to Colonel, February 24, 1865, for faithful and meritorious service; and breveted to Brigadier-General, U. S. Army, March 13, 1865, for gallant and meritorious services in the field during the Rebellion. He was promoted to Brigadier-General, U. S. Volunteers. April 5, 1865.

After the War, Dent served in garrison at Washington, D. C., August 26, 1865-April 10, 1866. He was on the Staff of the General-in-Chief, at Washington, D. C., May 3, 1866-May, 1873. During this period he was promoted to Lieutenant Colonel, Staff, Aide-de-Camp to the General- in-Chief, July 25, 1866 and Colonel, July 25, 1866. He was transferred to the 14th Infantry, August 21, 1866; commissioned Lieutenant Colonel, 32nd Infantry, December 31, 1867.

Dent served in command of Ft. Trumbull, CT, May 18, 1873-November 26, 1875; of St. Augustine, FL, December, 1875-July 1, 1881. He was made Colonel, 1st Artillery, January 2, 1881, and transferred to the 3rd Artillery, November 4, 1882. He retired on December 1, 1883. After his retirement he moved to Denver, CO where one of his sons was practicing law. He died there on December 23, 1892 and was buried at Arlington National Cemetery.